In a watch provided with an escapement, particularly a Swiss lever escapement, the escapement functions must be maintained regardless of any shocks experienced by the watch. The escapement must be robust and capable of resisting axial and radial shocks, in all positions of the watch. To achieve this, mechanical elements, called escapement safety devices, limit the travel of rotating or oscillating elements, in order to avoid any critical position which could either disrupt operation or stop the watch.
In particular, in a Swiss lever escapement, these safety functions are ensured by at least the horns and the guard pin. The reliability and robustness of this system are proven, but it nonetheless requires distinct components, which increases production costs and the risk of non-quality. The fact of arranging the horns and the guard pin on two distinct levels requires sufficient division, which has a significant impact on the height of the movement, and thus on the final thickness of the watch.
FR Patent No 206 876 in the name of WALD discloses a pallet lever with two horns that are symmetrical relative to a median plane, each with a concave inner profile and a convex outer profile.